High-velocity air-conditioning



1, 1959 c. ALLANDER ET AL 2,899,180

HI-GI-L-VELOCITY AIR-CONDITIONING 3 Sheets-Sheet 1 Filed Nov. 22, 1954 A 8" 11, 1959' 'c. ALLANDER ETA.

HIGH-VELOCITY AIR-CONDITIONING Filed Nov. 22, 1954 3 Sheets-Sheet .2

FIG. 2.

Aug- 1959 c. ALLANDER ET AL 2,899,180

' Filed Nov. 22, 1954 HIGH-VELOCITY AIR-CONDITIONING 3 Sheet s-Sheet 3 FIG-.3

L6 A; .4 L; A

Patented Aug. 11, 1959 HIGH-VELOCITY AIR-CONDITIONING Claes Allander, Jonkoping, Per-Olof Alfredsson, Bromma, and Sven Wallin, Jonkoping, Sweden, assignors to Aktiebolaget Svenska Flaktfabriken, Stockholm, Sweden Application November 22, 1954, Serial No. 470,486

Claims priority, application Sweden November 23, 1953 3 Claims. (Cl. 257-277) The present invention relates to high-velocity air conditioning a plurality of rooms in a building by means of injected air from one or more central air conditioning plants, the air being supplied with high velocity to th different rooms as primary air through a pipe system and being treated individually in the different rooms in separate room units, said units preferably being arranged at the windows of the rooms and provided with means for regulating the quantity of primary air and ejector means for recirculation of the air of the room and furthermore provided with means for conditioning of the air passing the units, a part of the air of room corresponding to the quantity of primary supplied air being evacuated in a manner known per se.

The invention is mainly based on the fact that the prior art conditioning systems for regulating the quantity of primary air to each of the connected rooms are not entirely satisfactory. When individually regulating the state of air in one room by changing the quantity of supplied air, each such change in the conventional air conditioning plants has influenced the quantity of primary air being supplied to the other rooms. For this reason in high pressure systems it has hitherto been usual to maintain the quantity of primary air distributed to each room as constant as possible, since a change in the quantity of primary air in a room has proved to involve serious difficulties with respect to air distributing, a disturbing high sound level and unpleasant draught by the supply of air to the other rooms. The maintenance of the quantity of air at a constant value has usually been performed by means of a damper fixed in a predetermined position. As stated above each change in one room has influenced the quantity of air in the other rooms and a great number of adjustments have been necessary before the quantities of supplied primary air in all the rooms have been adjusted to correspond substantially to the intended value.

It is a main object of the invention to eliminate the above mentioned drawbacks by automatically maintaining the quantity of primary air substantially constant after an individual adjustment in the dilferent rooms regardless of the pressure variations in the distributing pipe system resulting from changes in the quantities of primary air to the other rooms.

Another object of the invention is to eliminate any draught from the cool surfaces as for instance from winclows (down draught of cool air). The disadvantage of such draught has sometimes been eliminated in prior high pressure systems for air conditioning by blowing heated air along the cool surface. This, however, involves substantially increased losses of heat to the surface and is therefore an unsatisfactory solution of the draught problem. According to the invented method the secondary air inlet from the room is performed in such a manner that the down draught is utilized and constitutes a substantial part of the quantity of the ejected secondary air. A reduction in the running costs Will thus be gained as well as a greater comfort for the occupants of the room.

I The invention also involves valuable features with respect to the use of the cooling capacity of the plant and to the method for drawing off the primary air for the different rooms as compared with prior known systems for air conditioning of a plurality of rooms by means of air of high pressure. These features will be fully described in the following description with reference to the drawings.

The invention is characterized in that the quantity of the primary air supplied to each unit is automatically maintained constantly at a predetermined value independently of pressure variations in the pipe system and in that the ejected air of the room is caused to enter the unit at the top of same through an opening extending along the rear side of the unit, which air after being mixed with the primary air is discharged to the room from the top of the unit through an opening extending along the front side of the unit, the discharged air being regulated individually with respect to quantity and condition.

According to a preferred embodiment of the invention the rooms are divided into a number of zones, each zone being connected to a separate central conditioning plant for supplying primary air having a proper condition for said zone in accordance with its orientation in the'building.

The primary air is suitably given a varying condition in each central plant in accordance with the required cooling effect for the rooms connected to said central plant or on the contrary if heat is required a constant base temperature, preferably somewhat lower than the temperature of the air of the rooms.

When cooling effect is required the condition of the primary air from each of the central plans is determined automatically with respect to the outdoor temperature by means of a thermostat.

The necessary cooling of the primary air may in conventional manner be effected in the central conditioning plants by means of a cooling medium circulating through a cooling element. The capacity of the cooling element is regulated in correspondence with the required amount of cooling by a varying of the quantity of the cooling medium by means of a valve operated by a thermostat arranged after the cooling element, said thermostat in turn being dependent upon said out-door thermostat.

The supply of primary air to each room unit is performed in the manner that the primary air is drawn off around the tube for the primary air from the turbulent layer passing adjacent the tube wall.

The quantity of primary air for each room unit is maintained constant by causing the discharged (drawn olf) primary air to pass a volume governor arranged in each room unit.

Especially in high velocity system for air conditioning of a plurality of rooms connected to the pipe system it is important that the pipes and their connections are designed in such a manner that the pressure drops owing to friction, bends and so on are maintained as small as possible. It is also important that the recovery of the static pressure is maintained as great as possible when the dynamic pressure at each discharge point is reduced. By drawing off the discharge air in the usual manner by means of T-fittings and similar elements only a small part of the dynamic pressure difference is, however, recovered to useful static pressure. According to the present invention the above mentioned drawing off is performed by a symmetrical drawing 01f. Such drawing off has proved to give a very great recovery of pressure in the common supply pipe for the primary air. The discharged quantity of air is thus drawn olf from the turbulent air layer adjacent to the inner Wall of the pipe. This results in that the main air current will expand diffuser-like practically without any losses. This shaving-off is preferably accomplished by means of one or more apertures symmetrically arranged around the pipe for the primary air.

In high velocity systemsfor air conditioning a plurality of rooms connected to a pipe system where cold air is used as cooling medium for the different rooms it has proved very difiicult-when using pipes insulated in a conventional mannerto prevent the water vapour of the room' air from penetrating the insulation and condensing on the cool wall of the'pipe. According to the present invention this drawback is eliminated by using distributing pipes consisting partly of an outer tube, which is made absolutely air-tight as against the" surrounding air of the room and partly of an inner tube arranged coaxially with respect to the outer tube. It is not necessary to make the inner tube quite air-tight. The insulation of the distributing pipes consists according to the invention preferably only of the air layer in the annular space between the two tubes.

In order to prevent the heat contents of the exhausted room air from being lost it is proposed according to the invention that the exhausted air is caused to pass a heat exchanger and preheat and humidify, if required, the out-door air which is supplied to the central conditioning plant(s).

The apparatus according to the invention is mainly characterized in that each room unit at its bottom is provided with a chamber, connected to the pipe for the primary air, said chamber being provided with means for automatically maintaining a constant, predetermined quantity of supplied primary air independently of pressure variations in the pipe system for the primary air. The chamber is connected with the upper part of the room unit by means of a horizontal partition provided with one or more ejector nozzles, and the upper part by means of a vertical partition is divided in two spaces. One of said spaces situated adjacent the rear side of the'unit' constitutes a supply channel for recirculated air from the room, said channel communicating with the room through an opening at the top side of the room unit, which opening extends along the rear edge of said top side and is provided with a grille. The other space adjacent the front side of the unit is provided with a conditioning means and with a by-p'ass and a regulating valve, and at the top side along the front edge of the unit is provided with an opening for the discharge of treated air into the room. Other characteristics and arrangements will be evident from the claims and the following description.

The invention will now be more fully describedwith reference to the accompanying drawings, where Fig. 1 is a perspective view of the entire apparatus.

Fig. 2 is a vertical section of one of the room units along the line 22 in Fig. 3 and Fig. 3 is a vertical longitudinalsection of said unit along the line 3-3 of Fig. 2.

In Fig. 1, an inlet 1 for out-door air is provided with a damper 2 and connected by means of a channel-3 with a heat exchanger 36, in which the channel terminates at the opening 6. A channel 4, 14 is also connected to the heat exchanger, said channel being connected to a collecting enclosure 49 for air being exhausted from the difierent rooms. The last mentioned channel terminates in the heat exchanger 36 at the point 37. After the heat and moisture contents of the air exhausted from the rooms have been utilized in the heat exchanger 36 this air is carried away from the heat exchanger through the opening 8 to the channel 22 and further by means of a fan 21 to the atmosphere via the channel 19. Said channel 19 is provided with an outlet 13. If the air exhausted from the rooms is not to be utilized for heat and moisture exchange with the supplied out-door air, said exhausted room air is conducted directly from the channel 14 to the channel 22, a damper 9' being closed and a damper 11 opened, thus opening the passage 12. In the cases when the heat exchanger" 36' is not to be used, the inlet of the out-door air can take place through achannel 23'via' the opening 17 provided with a grille 16 and by opening the damper 18; The supplied outdoor air in this case conducted through the channels 24 and 26 directly to the inlets 27 of the air conditioning plants 33. Each of the separate air conditioning plants consists of a number of sections 28, 29 and 31, 32 comprising for instance filtering means, humidifying means, cooling and heat elements; The air conditioning plants are furthermore equipped with a fan 34 for conveying the air being treated in the heat conditioning plant via a duct 38 to one or more distributing chambers 39, which chambers furthermore are used as sound traps. A cooling compressor 41 by means of pipes (not shown) is connected with the cooling elements of the heat conditioning plants. In-the drawing 42, 43 and 44,- 46 designate a pipe system for distributing air treated in the air conditioning plant, which air is intended to be supplied to different room units 47 by. means of said pipe system.

The above-described apparatus also includes an arrangement for exhausting of waste air from the rooms. For this purpose each room is provided with an exhausting grille 48. The exhausting grilles of the different rooms terminate suitably in the enclosure 49 formed by for instance inserting an additional ceiling 50a in a corridor 50. The enclosure 49 communicates by means of a vertical channel 15 with the previously mentioned channel 14. As described above the air being collected in the enclosure 49 and the channels 15, 14 may be supplied to a heat exchanger in order to utilize the heat contents of air for the purpose of gaining a better heat economy.

Figures 2 and 3 show an exemplifying form of the room units. As shown each room unit is arranged immediately in front of and below the windows 52 of the rooms 100. The top side 57 of the unit is arranged flush with the window sill 53. The casing of the unit is designated 66. Two openings 54 and 62, provided with grilles 54a and 62a, extend along the rear side and the front side of the unit respectively. The room air 51 passing along the window surface 52 is drawn to the space 56 through the opening 54, which space 56 is located behind a vertical partition 61 in the upper part of the unit, said space being formed by a'recess in the wall 99. The arrows 59 designate the flow direction of the air. The air drawn in from the room, i.e. the so-called down draught of cool air, is forced to pass through the space 58 and the opening 72 to a mixing chamber 68 in the upper front part of the unit. This room air can, if desired, be complemented with air supplied through one or more openings at the sides and also at the bottom of the said unit. Said openings communicate with the chamber 68.

A pipe 89, through which the air treated in the previously mentioned air conditioning plant 33 is supplied as primary air to the room unit, communicates with one of the pipes 42, 43 and 44, 46 connected to the distributing chamber 39. The pipe 89 consists of two concentric tubes 90a, 90b as evident from Fig. 3. This prevents the water vapour of the room air from condensing on the cool wall 90a in case the pipe 89 is to transport cool air as cooling medium to the different rooms. According to the invention the outer tube 90b for this purpose must be air tight against the surrounding room air.

The drawing-off of primary air to each unit is performed symmetrically around the pipe 89, which pipe for this purpose is provided with apertures 88 evenly distributed around the cylindrical surface of the inner tube 90a. By drawing-0E in this special manner only the air layer adjacent the tube wall is discharged at each room unit and the reduction of velocity will thus occur with very small losses resulting in that the recovery into static pressure will be very great. It has proved that this way of discharging a certain quantity of air to each unit 47 involves a reduction of the velocity for the main current of air substantially without any losses and that the recovery will substantially compensate the friction losses in the distributing pipe system between the different room units 47. The room units are arranged in groups and connected in series to one of the distributing pipes 42, 43 and 44, 46. The pipe 89 is thus a part of one of these distributing pipes.

The lower part of the room unit 47 surrounding the primary air pipe 89 is formed as a chamber 91, said chamber at its top being provided with a horizontal wall 84. This wall 84 is provided with one or more volume governors 86, which are intended to maintain the quantity of primary air supplied to the space 83 at a constant value independent of pressure variations in the distributing pipe 89, which variations are caused by manual changes of the quantity of primary air by its discharge at other room units. By using more than one volume governor in one and the same room unit, the quantity of air treated in the room unit can be varied Within wide limits at the same time as a predetermined constant quantity of air may automatically be maintained. Such an individual change of air quantity may be desired to vary the supply of primary air in accordance with the different seasons of the year. If for instance three such governors are usedeach of which being able to maintain a supply quantity of air at a constant value amounting to 20 mfi/hour-one or more of these governors may be put in and out of function to provide volumes ranging from 20 to 60 cubic meters per hour.

The space 83 is preferably equipped with a sound trap 82, 79. The flow direction of the primary air is illustrated by the arrows 85, 81, 78. 77 designates an ejector means provided with the openings 76 through which the primary air is introduced into the mixing chamber 68. The ejector means may suitably consist of one or more rows of jets, arranged to be closed and opened respectively. By this arrangement the proportion between the quantity of room air (so-called secondary air) supplied from the space 56--58 and the quantity of primary air supplied through the pipe 89 can be varied. Secondary and primary air are usually mixed in the proportion 2: 1.

The mixing chamber 68 is provided with a separate conditioning means 69. Said means is separated from a by-pass 68a by means of a partition 70c. 71 designates a moveable damper blade, which blade manually can be moved to shut oit the inlet 70b to the conditioning means 69. In this position the damper blade is designated 71a. The damper blade can also be moved to shut ofi the by-pass 68a entirely or partly. In the position for shutting oif the bypass entirely the damper blade is designated 71b. The outlet of the conditioning means 69 is designated 70a. 67 and 64 designate the flow direction of the air in the by-pass and after the conditioning means respectively. The arrow 60 designates the direction of the treated air discharged into the room 100.

The space 92 also belongs to the room unit 47, which space at its bottom is limited by a plate 94. The pipes 93 are arranged in this space 92. Said pipes supply the necessary medium for the conditioning means 69. The pipes 93 are connected with the coils of the conditioning means 69 by means of the pipes 103. 101 designates fins for the increasing of the effective surface of the conditioning means 69. As the room unit always is manufactured in one and the same standard size, there will in certain cases be a space 96 between the room unit and the floor 98 of the room. This space is closed by means of a front plate 97.

The function of the apparatus and the method for air conditioning is evident from the description above. Still another feature of the object of the invention is to be pointed out. In prior systems using air of low temperature as cooling medium for the different room units, the cooling capacity has not been automatically adjusted to the needed cooling elfect necessary at different times. It can therefore happen that the cooling capacity can be unnecessarily great, especially in the periods between difierent seasons. This can be balanced in the room units by a secondary heating in a heating element. According to the invention the cooling capacity for each Zone is adjusted with respect to the prevailing need at each moment. There is normally no need for any secondary heating and neither is it necessary to change the individual adjustment in the room unit because of variations in the outside conditions after each of the units has been adjusted for a desired room-climate. This can be done practically by means of a thermostat, arranged after the cooling element and governed by an out-door thermostat, which thermostat influences either a motor for a damper device in the air currenti.e. two dampers for the cooling element and a by-pass (one of said dampers closing, while the other is opening)or said thermostat can influence a motor-operated valve in the pipe for the cooling medium.

What we claim:

1. For air conditioning a room having a window, a conditioning unit adapted to be mounted below said window comprising a casing, a partition dividing the upper part of said casing into two channels, the first of said channels disposed adjacent said window and the second of said channels disposed outwardly of said Window, a secondary air inlet in the top of said unit opening into said first channel, an air outlet in the top of said unit opening into said second channel, said secondary air inlet disposed intermediate said outlet and said window, ejector means at the lower end of said second channel for directing primary air upwardly through said second channel, supply means for supplying conditioned primary air to the ejector means, throttling means in said casing intermediate said supply means and said ejector means responsive to the pressure variation in the supplied primary air for maintaining automatically said primary air quantitatively constant, means adjacent the lower end of said second channel for mixing said secondary air from said first channel with the primary air in said second channel, means above said lower end of said second channel for regulating the condition of said mixed air in said second channel during its upward travel therethrough, whereby the regulated mixed air is discharged in a curtain through said outlet in the top of said unit.

2. A device according to claim 1 wherein said throttling means includes regulating means for adjusting the quantity of conditioned primary air injected into said unit in accordance with the season of the year.

3. A conditioning unit according to claim 1 wherein said supply means for primary air includes a distributing conduit passing through said unit, said conduit having substantially symmetrically arranged openings about the periphery thereof for the discharge of the turbulent peripheral layer of the primary air in the conduit into said throttling means.

References Cited in the file of this patent UNITED STATES PATENTS 1,949,735 Bulkeley Mar. 6, 1934 1,990,895 Callahan Feb. 12, 1935 2,072,166 Goodman Mar. 2, 1937 2,159,276 Lawless May 23, 1939 2,290,985 McElgin July 28, 1942 2,363,945 Carrier Nov. 28, 1944 2,705,595 Carlson et al Apr. 5, 1955 2,729,429 Goemann Jan. 3, 1956 ,7 7,94 Gannon Apr. 9, 1957 

